This invention is directed to mica based pigments that are coated with an alkylene glycol alkyl ether that can be readily incorporated into all types of coating compositions or paints such as alkyd resin paints, solvent based acrylic polymer paints, polyurethane paints and water based acrylic polymer or polyurethane paints.
Mica based pigments are known in the art and have been used in coating compositions to provide unique finishes having a pearlescent appearance. Mica based pigments wherein mica flakes are coated with titanium dioxide pigment and to provide color are coated with mixtures of titanium dioxide pigment and metallic oxide pigments such as iron oxide are shown in Linton U.S. Pat. No. 3,087,828 issued Apr. 30, 1963, Brand et al U.S. Pat. 3,711,308 issued Jan. 16, 1973 and in Armanini et al U.S. Pat. No. 4,146,403 issued Mar. 27, 1979.
Incorporation of these mica based pigments into coating compositions can be accomplished by the usual method by first forming a dispersion or mill base of the pigment and then blending the dispersion with the coating composition. A typical dispersion contains the mica based pigment, a liquid carrier which may be solvent or water and a polymeric dispersant. The dispersion is blended or mixed with the coating composition to obtain a desired color for the coating composition. These dispersions have obvious disadvantages of being liquids that must be compatible with the coating composition and therefor, a number of dispersions must be utilized for different types of coating compositions such as waterborne compositions, solvent based compositions, compositions having different film forming binders such as acrylic polymers, alkyd resins, epoxy resins, epoxy ester resins, polyurethanes, polyesters and the like. It would be desirable to be able to mix or blend the mica based pigment directly into the coating composition and eliminate forming a dispersion of the pigment. This cannot be done with untreated pigment since it will not readily blend into the coating composition and will either float on its surface or agglomerate or both.
The novel treated mica based pigment of this invention can be blended into all types of coating compositions including waterborne or solvent based compositions that are formed with a variety of film forming polymers.